(a) Field of the Invention
The present invention relates to a photosensitive material for use in electrophotography, in particular a photosensitive material comprising a photoconductive layer on which there is a protective layer consisting essentially of a substance resulting from partial hydrolysis of a composition (mixture) of (a) a silane coupling agent, (b) an acryl resin having a silane radical copolymerized with styrene, acrylic acid, maleic acid, etc., and (c) a diorganopolysiloxane with terminal hydroxyl radicals at both ends of the molecular chain.
(b) Description of the Prior Art
Electrophotographic photosensitive materials comprising a conductive substrate on which there is a photoconductive layer of an inorganic or organic semi-conductor are well known. And, the so-called Carlson process is employed therein for the purpose of forming an electrostatic latent image thereon, said process comprising electrifying the surface of the photoconductive layer and then subjecting the thus electrified material to an imagewise exposure. However, these photosensitive materials have been defective in that the photoconductive layer, being exposed, is deteriorated in mechanical strength and consequently is very often destroyed by repeated use.
For this reason, various photosensitive materials have been proposed to improve the durability of conventional materials by further providing a transparent protective layer on the photoconductive layer. And the materials used for the formation of said protective layer such as polyethylene, poly-n-butylmethacrylate, polyamide, polyester, polyurethane, polycarbonate, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, ethyl cellulose, cellulose acetate, polyethylene terephthalate, polyethylene terephthalate-polyethylene isophthalate copolymer, etc. are well known. These materials surely have some merit in protecting the photoconductive layer, but are defective in that they are not always sufficient in their durability and are liable to hamper the formation of stable images under the influence of humidity and changes in humidity.
In addition, Japanese Laid-open Patent Applications No. 96229/1975 and No. 23636/1978 disclose photosensitive materials wherein a certain kind of silicon compound has been incorporated in the protective layer in a fixed quantity to improve its durability. These photosensitive materials are surely superior in the properties such as hardness, abrasion resistance, etc., but are somewhat inferior in their adhesive property. The fact is that in particular when the photoconductive layer comprises a metal such as Se, Se-Te or the like or a metal sulfide such as CdS, the adhesion between the protective layer and the photoconductive layer is liable to become so insufficient that a photosensitive material of a desired degree of durability is not obtainable.